Note: Descriptions are shown in the official language in which they were submitted.
3 PCT/EP90/00129
04~ og
Textile fabric shielding electromagnetic radiation,
and clothing made thereof
The invention concerns a textile fabric shielding
electromagnetic radiation, and clothing made thereof.
From DE-A-29 23 286, a textile fabric is known whose
orthogonally crossing warp threads and weft threads are made of
spun mixed yarn of steel fibres of stainless steel and of
textile fibres. The steel fibres may be extremely thin, less
than 25 micrometers in diameter, for example. According to this
document, the mesh is proposed to measure at least O.5 cm2.
This textile fabric is designed for carpet floors or working
g~rmpnts~ for example, in order to obtain an antistatlc network
and thus prevent electrostatic charging.
.
However, such a fabric does not provide effective protection
against microwaves and other electromagnetic radiation, to
which in particular the hospital personnel, for example, when
operating electromedical equipment such as X-ray, ECG and EEG
apparatus and the like, and the personnel for operating radar
installations, for example, are exposed. In the course of
electronization, also heart pacemakers are mini~turized and
refined, but at the same time rendered susceptible to
. 25 electromagnetic radiation interference such as occurrs in
everyday life due to, for example, broadcast and TV stations
arnd various electrical apparatus, electric motors, electrical
and electronic ignition control devices in motor vehicles,
shavers, electrical household appl; ~ncP~, and electronic
computer installations and the like. Nodern heart pacemakers
are designed so as to ta~e over the pacPm~kPr function only
when the normal heart rhythm is disturbed, but not to interfere
when the heart rhythm is normal. The occurrence of
electromagnetic radiation, however, may result in a dist~rh~nce
3~ of the heart pacema~er control such that incorrect information
on the current heart activity may be received and the control
may fail in that case.
t
2045409
While it is true that clothing which shields against
electromagnetic radiation exist, such as the vest known
from US-A-4 196 355. However, this vest, due to its
construction and weight, is much too heavy and
uncomfortable to be suitable for normal applications.
According to the invention, a textile fabric and clothing
made thereof are provided, which are effectively suitable
for shielding against electromagnetic radiation, in
particular in the microwave range, and, at the same time,
do not restrict the wearing comfort of usual clothing.
The invention is based on the perception that total
shielding against electromagnetic radiation is not
necessary, since radiation below certain intensities can be
accepted without health impairment, and that this provides
the possibility of achieving sufficient shielding by means
of clothing even without restriction on the wearing
comfort.
In accordance with an embodiment of the present invention
there is provided a textile clothing fabric comprising
orthogonal crossings between warp threads and weft threads,
the threads being made of stainless steel fibers and
textile fibers blended together and spun into mixed yarn,
wherein the textile fibers comprise cotton fibers and are
twined with the steel fibers, the steel fibers measure 6 to
10 micrometers in diameter and constitute a content of 10
to 15~ per weight of the mixed yarn, the distribution of
the warp threads and the weft threads in the fabric and the
B
- 2a - 2045409
composition of the warp threads and the weft threads being
substantially the same, the number of mixed yarn threads in
warp direction and in weft direction each is 18 to 20
threads per cm, the yarn fineness of the textile fabric is
in the range of 30 to 50 tex, a part of the steel fibers is
exposed on the exterior surface of the mixed yarn and
mutual electrical contact exists between the warp and weft
threads at said crossings to form a Faraday cage, such that
a shielding by 20 to 40 dB against electromagnetic
radiation at a frequency of 10 GHz is established by the
fabric.
Owing to the content and fineness of steel fibers suggested
in
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accordance with the invention, a textile fabric suitable for -
effecti~e shielding against excessive electromagnetic microwave
radiation can be obtained in a clothing fabric quality, which
textile fabric is not too stiff. Hence, clothing can be made
which is comparable to clothing without steel fibers. For the
shielding effect, it is essential that the steel fibers and the
textile fibers are spun and twined with each other in a manner
such that a substantial part of the steel fibers is exposed on
the exterior surface of the mixed yarn and sufficient mutual
electrical contact of the fibers is achieved in the warp and
weft threads at the crossings of the fabric to form a Faraday
-- cage. The average number of the steelfibers in the yarn
cross-section is preferably 10 to 15.
Preferably, the thickness of the steel fibers measures 8
micrometers, and the content of the steel fibers in the mixed
yarn is preferably 13,5 % per weight. The length of the steel
fibers is preferably in the range of the length of the cotton
fibers and, hence, measures 3 to 10 centimeters. Although it is
further possible to~provide a mixture of cotton fibers and
polyamide fibers, it is preferred to provide textile fibers
exclusively of cotton. Cotton is capable of absorbing moisture
and improves the electrical conductibility with increasing
moisture absorption.
-25
Although a twined one-thread yarn, i.e., a yarn only
single-twined, may be used, it is preferred to use a mi xe~ yarn
made of double-twined mixed yarn threads, each of which is made
of textile fibers and steel fibers in a twined ~nn~r, wherein
the single threads have a yarn fineness of 16 to 20 tex and a
degree of turns of 550 tD 650 turns, especially Z-turns, per m,
and wherein the degreeiof turns of the double-threads is 400 to
480 turns, especially Z-turns, per m.
The textile fabric according to the invention is light (the
weight of the textile fabric is preferable in the region of 160
g per mZ) and p~rm~hle to air and washable like other cloths
without impairment of the shielding effect against
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e~l ectromagnetic radiation as would be the case if there were no
aiscrete steel fibers but, instead, for example, a metal
coating of the textile fibers. Moreover, the textile fabric
according to the in~ention may be dyed such that pleasing and
fashionable articles of clothing can be made of it.
A textile fabric according to the invention having been proved
and being excellently effective to shield heart pacemaker
against microwave radiation was made of pure cotton with spun
with steel fibers. The warp threads and weft threads were made
of double-twined yarn of a fineness of R 38 to 40 tex made of
single-threads of a fineness of R 16 to 18 tex. The degree of
turns of the single threads was 5gO to 640 Z per m and that of
the Yarn was 420 to 440 Z per m. The content of steel fibers
spun into the single-threads was about 13,5 ~ per weight of the
mixed yarn. The thread density of the textile fabric was 18 to
20 threads per:cm, each, in warp direction and in weft
direction and the average weigth of the textile fabric was 160
g per m~. The textile fa~ric had an elongation of g to 14 % at
a breaking force of 638 to 672 N. -
.
The clothing according to the in~ention is completely or partly
made of a textile fabric according to the in~ention. This
textile fabric may completely form the clothing or may be
provided as its interior lining. It is also possible to line i
the textile fa~ric itself with a lining of different textile
mater;~l. For the manufacture of this textile fabric, usual
pieces of fabric are cut out which are sewed together along
joint se~ms. According to the invention, it is essentlal that
the textile fabric is made of the abo~e-presented
textile/steel-fiber fabric according to the in~ention and
covers at le~st the up er part of the body and the hip area of
the person wearing the clothing as well as at least the
person~s upper arms approximately to the elbows. To a~oid
intelru~Lion of the shielding effect in the area of the joint
seams, the joint seams should be turned up into each other and
sewed together by at least two seams with a sewing yarn that is
also a textile-fiber/steel-fiber mixed yarn of the ~lnd
~ WO90/09473 - -
~` 2 0 4 5 4 0 9 PCT/EP90/00129
,
according to the invention. However, the content of steel
fibers in the sewing yarn may possibly be greater than the
content in the threads of the textile fa~ric. A11 fasteners of
the clothing, such as zip and button fasteners, should be free
of metal and be underlayed with an interior border band or flap
- made of the textile-fiber/steel-fiber fabric according to the
invention and provide an overlap breadth of at least 5 and
preferably 7 centimeters. If pockets are provided in the
textile fabric, these pockets should not be inserted into but
put on the fabric, in order to avoid interruptions of the
shielding effect.
~ In a preferred embo~;ment of a clothing according to the
invention, the clothing is in the form of a shirt or T-shirt
which has at least elbow-length sleeves, covers the hip area of
the person wearing the shirt and is provided with a closable
neckline that, even when not closed, is covered by an interior
flap made of the textile-fiber/steel-fiber fabrlc according to
the invention. As proven by numerous experiments, such a
clothing is most suitable for wearers of heart pacemakers to
attain an effective shielding of the heart pacemakër against
electromagnetic radiation disturbances and, at the same time,
achieving the wearing comfort of other shirts or T-shirts.
Owing to the invention, shirts or T-shirts o~ this kind may be
~- 25 manufactured in such a way that they look like other shirts or
T-shirts and, hence, the fact that a person needs a heart
pacemaker is not discernible from this kind of clothing.
In another preferred embodiment, clothing according to the
invention suitable for the personnel of radar installations
takes the shape of an oyerall, in which the
textile-fiber/steel-fiber fabric according to the invention
covers the upper part of the body as well as at least the upper
arms and the hip area, at least down to the knees.
3S
As protective clothing for hospital staff against the influence
of electromaqnetic radiation emitted by electrome~;ca~
apparatus, two-piece clothing co~sist~ng of a jacket or blouse
WO90/09473
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6 '~ -
and a pair of trousers is suggested, wherein the pair of
trousers is o~erlapped by the jac~et or blouse by at least 10
centimeters and the jac~et or blouse in its chest area has
overlapping parts of textile-fiber/steel-fi~er fabric held
toqether by Velcro-type fasteners. Since clothing according to
-! the invention is made of comfortable textile material, it can
be worn completely closed, while the Velcro-type fasteners
prevent the jacket or blouse from being worn open. In this
arrangement, one of the overlapping parts of textile fabric
preferably extends to one shoulder of the wearing person, and
the other part of textile fabric extends at least to the middle
of the person's body. The waist measurement of the trousers of
this clothing is preferably also adjustable by me~ns of
Velcro-type fasteners. In such clothing according to the
invention, an interior 1 ;ning may be formed of the
textile-fiber/ steel-fiber fabric according to the invention.,
while the exterior side of the clothing may, for example, made
of light cotton cloth of a ~uality usual for hospital clothing.
20 - When the clothing according to the invention is embodied by an
overall or two-piece suit, a stand-up collar cont~; n; ng textile
fabric material according to the invention is preferably
additionally provided.
,
The invention will now be explained with regard to clothing
according to the invention and depicted in the drawings. In the
dr=awing:
Fig. 1 illustrates clothing according to the invention in the
form of a T-shirt or shirt,
Fig. 2 illustrates clothing according to the invention in the
form of an overat'-i,
Figs. 3 to 5 illustrates clothing according to the invention in
the fo~m of a two-piece suit from the front, lateral
and rear sides,
Figs. 6 and 7 illustrate front and side views o~ the jac~et of
the clothing according to Figures 3 to 5,
~igs. 8 and 9 illustrate front and side ~iews of pair of
` ~090~09473 PCT/EP90/00129
7 ~ 20~5~9
trousers of the clothing according to Figures 3 to S,
and
Fig. 10 illustrates the design of the joint seams of the
clothing according to Figures 3 to ~.
The T-shirt or shirt according to Fig.1 is provided for persons
wearing a heart pacemaker and is designed to shield the heart
pacemaker against electromagnetic radiation, especially in the
microwave range. For this purpose, the T-shirt is made of the
fabric described in detail above which is woven from a mixed
yarn of cotton and steel fibers intertwined with each other.
The T-shirt completel~ covers the upper part of the body of the
wearer, and clearly extends with its lower rim 6 beyond the hip
area of the wearer. The neckline 2 of the T-shirt equipped with
a folded collar 1 can be closed by me~n~ of a zip ~astener 3 of
plastic material, the zip fastener being underlayed with an
interior flap 4 completely covering the nec~line 2 even when
the zip fastener 3 is completely open. The interior flap 4 is
made of the same textile fabric material as the other parts of
the T-shirt, whose sleeves 5 are elbow-length so that no
detrimental radiation can intrude laterally from the sleeves S,
either. These sleeves 5 should be at least 20 centimeters long.
The overall according to Fig.2 may, for example, be used as
~5 wor~ing clothing for radar personnel and is also made of the
textile fabric parts according to the invention. The overall
can be closed up to the upper rim of the stand-up collar 7 by
m~n~ of the zip fastener 3, is also made of plastic material,
and is underlayed over its entire length with an interior
border band ~not shown) which is at le2st 7 centimeters broad
and made of the textile /fabric material. The poc~ets 10 are put
on the textile fabric material and sewed to it. These poc~ets
may be made o~ a different textile cloth.
The two-piece protective suit according to Figures 3 to 9 is
provided as protective clothing for hospital personnel exposed
to microwave radiation arising from electromedical apparatus.
The jac~et, as well as the trousers of this protective suit,
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are made of an outer cloth such as light cotton fabric material
developing no protective effect, and of a lining made of the
textile fabric material according to the invention. ThiS lining
extends over the entire clothing. The front part of the jacket
S has a widened outer portion 14 extPn~ing up to one shoulder and
an inner portion 13 extending with its interior border 17 to
the middle of the chest. The jacket is closed by means of
Velcro-type fastener strips 18 when laying together the outer
portion 14 on the inner portion 13. The jac~et 15 is provided
with a stand-up collar 7 and elbow-length sleeves 5.
The pair of trousers 16 can be closed in the front by means of
a zip fastener 3 which is underlayed with a particularly wide t
interior border band 21 of a width of at least 5 centimeters.
The waist measurement of the trousers is adjustable by means of
Velcro-type fastener strips 18. In addition, the trousers have
put-on pockets 10.
The respective clothing according to Figs. 1 to 9 are tailored
of fabric pieces which are sewed together along joint seams 19.
As can be seen from Fig.10, the joint seams 19 are turned up
into each other and sewed together by at least two seams 20.
